Fix Broken Links & Harden Site

I have discovered well over ten broken links scattered throughout my website, hurting both user experience and SEO. I need a systematic crawl, confirmation of every faulty URL, and then permanent, search-engine-friendly... (Budget: ₹750 - ₹1250 INR, Jobs: Internet Security, PHP, SEO, Web Design, Web Development, Web Scraping, Web Security, Website Audit)